Microbiome and skin biology Purpose of review The skin is home to a diverse milieu of bacteria, fungi, viruses, bacteriophages, and archaeal communities. The application of culture-independent approaches has revolutionized the characterization of the skin microbiome and have revealed a previously underappreciated phylogenetic and functional granularity of skin-associated microbes in both health and disease states. Recent findings The physiology of a given skin-niche drives the site-specific differences in bacterial phyla composition of healthy skin. Changes in the skin microbiome have consistently been associated with atopic dermatitis. In particular, Staphylococcus aureus overgrowth with concomitant decline in Staphylococcus epidermidis is a general feature associated with atopic dermatitis and is not restricted to eczematous lesions. Changes in fungal species are now also being described. Changes in the composition and metabolic activity of the gut microbiota are associated with skin health. Summary We are now beginning to appreciate the intimate and intricate interactions between microbes and skin health. Multiple studies are currently focused on the manipulation of the skin or gut microbiome to explore their therapeutic potential in the prevention and treatment of skin inflammation. Correspondence to Liam O’Mahony, Office 450, 4th Floor Food Science and Technology Building, University College Cork, Cork, Ireland. Tel.: +353 21 4901316;. e-mail: liam.omahony@ucc.ie Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.